Method and apparatus for operating an emission abatement system

ABSTRACT

A method for operating an emission abatement assembly ( 10 ) includes determining if a particulate filter ( 18 ) needs to be regenerated and adjusting the operation of an internal combustion engine ( 12 ) to increase oxygen content in exhaust gases generated by the engine ( 12 ) to generate heat in a fuel-fired burner ( 16 ) for combusting soot trapped in the particulate filter ( 18 ). An emission abatement assembly ( 10 ) is also disclosed.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to an emission abatementdevice, and more particularly to a method of operating an emissionabatement device including a regeneration device for particulatefilters.

BACKGROUND

Untreated internal combustion engine emissions (e.g., diesel emissions)include various effluents such as NO_(X), hydrocarbons, and carbonmonoxide, for example. Moreover, the untreated emissions from certaintypes of internal combustion engines, such as diesel engines, alsoinclude particulate carbon-based matter or “soot”. Federal regulationsrelating to soot emission standards are becoming more and more rigidthereby furthering the need for devices and/or methods which remove sootfrom engine emissions.

The amount of soot released by an engine system can be reduced by theuse of an emission abatement device such as a filter or trap. Such afilter or trap is periodically regenerated in order to remove the soottherefrom. The filter or trap may be regenerated by use of a burner toburn the soot trapped in the filter. The use of a burner to burn sootraises the temperatures of exhaust gases flowing through the enginesystem, which are eventually released into the atmosphere.

SUMMARY

According to one aspect of the disclosure, a method for operating anemission abatement system may include determining if a particulatefilter needs to be regenerated and generating a signal in responsethereto. In response to the generation of the signal, a operation ofinternal combustion engine may be adjusted to increase the oxygencontent in exhaust gases generated by the engine. The exhaust gases maybe advanced to a fuel-fired burner. Heat may be generated with thefuel-fired burner to combust soot trapped in a particulate filter.

According to another aspect of the disclosure, an emission abatementassembly may comprise an internal combustion engine, a particulatefilter, a fuel-fired burner, and a controller. The fuel-fired burner maybe positioned upstream of the particulate filter. The controller may beelectrically coupled to the internal combustion engine and thefuel-fired burner. The controller may comprise a processor and a memorydevice electrically coupled to the processor. The memory device have mayhave a plurality of instructions stored therein that may be executed bythe processor. The execution of the instructions may cause the processorto determine if the particulate filter needs to be regenerated andgenerate a control signal in response thereto. The execution of theinstructions may further cause the processor to adjust the operation ofthe internal combustion engine to increase the oxygen content in exhaustgases generated by the engine in response to the generation of thecontrol signal. The execution of the instructions may also cause theprocessor to operate the fuel-fired burner to generate heat to combustsoot trapped in the particulate filter in response to the generation ofthe control signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatical schematic of an exemplary embodiment of anemission abatement system.

FIG. 2 is a diagrammatical schematic of another exemplary embodiment ofan emission abatement system.

FIG. 3 is a diagrammatical schematic of another exemplary embodiment ofan emission abatement system.

FIG. 4 is a diagrammatical schematic of another exemplary embodiment ofan emission abatement system.

DETAILED DESCRIPTION OF THE DRAWINGS

As will herein be described in more detail, an emission abatementassembly 10 for use with an internal combustion engine, such as a dieselengine 12, includes a soot abatement assembly 14. As shown in FIG. 1,the soot abatement assembly 14 has a fuel-fired burner 16 and aparticulate filter 18, respectively. The fuel-fired burner 16 ispositioned upstream (relative to exhaust gas flow from the enginerepresented by the arrows in FIG. 1) from the particulate filter 18.During operation of the engine 12, exhaust gases flow through theparticulate filter 18 thereby trapping soot in the filter 18. Treatedexhaust gases are released into the atmosphere or directed to otherdownstream (relative to exhaust gas flow) emission abatement devicesthrough exhaust outlet 20. From time to time during operation of theengine, the fuel-fired burner 16 is selectively operated to regeneratethe particulate filter 18.

When operated, the fuel-fired burner 16 receives a supply of fuel toproduce a flame that heats exhaust gases flowing through an exhaust line27. The heated exhaust gases are advanced downstream to the particulatefilter 18 and ignite the soot trapped therein. The fuel-fired burner 16must sustain a flame capable of heating the exhaust gases flowingtherethrough to a temperature high enough to ignite the soot in theparticulate filter 18. In order to achieve a sufficient temperature, thefuel-fired burner 16 requires a sufficient amount of oxygen forcombustion, and thus the heating of the exhaust gases. However, exhaustgases produced by an engine such as the engine 12 during typicaloperation may not contain enough oxygen to allow the fuel-fired burner16 to reach regeneration temperatures. Supplemental air supplies havebeen previously used, which may be configured along an exhaust path toprovide air to a fuel-fired burner for combustion. However, theoperation of the engine 12 may be adjusted by methods described hereinto produce exhaust gases containing a sufficient amount of oxygensupplied to the fuel-fired burner 16 for regeneration of the filter 18.Once the fuel-fired burner 16 is activated, it begins to produce heat.Such heat is directed downstream by the exhaust gases and into contactwith the upstream face of the particulate filter 18. The heat ignitesand burns soot particles trapped in the filter substrate therebyregenerating the particulate filter 18.

The particulate filter 18 may be any type of commercially availableparticulate filter. For example, the particulate filter 18 may beembodied as any known exhaust particulate filter such as a “deep bed” or“wall flow” filter. Deep bed filters may be embodied as metallic meshfilters, metallic or ceramic foam filters, ceramic fiber mesh filters,and the like. Wall flow filters, on the other hand, may be embodied as acordierite or silicon carbide ceramic filter with alternating channelsplugged at the front and rear of the filter thereby forcing the gasadvancing therethrough into one channel, through the walls, and outanother channel. Moreover, the filter substrate may be impregnated witha catalytic material such as, for example, a precious metal catalyticmaterial. The catalytic material may be, for example, embodied asplatinum, rhodium, palladium, including combinations thereof, along withany other similar catalytic materials. Use of a catalytic materiallowers the temperature needed to ignite trapped soot particles.Illustratively, heat in the range of 600-650 degrees Celsius may besufficient to regenerate a non-catalyzed filter, whereas heat in therange of 300-350 degrees Celsius may be sufficient to regenerate acatalyzed filter.

In one exemplary embodiment, regeneration of the particulate filter 18may take only a few minutes. Moreover, it should be appreciated thatregeneration of the particulate filter 18 may be self-sustaining onceinitiated by heat from the fuel-fired burner 16, respectively.Specifically, once the filter 18 is heated to a temperature at which thesoot particles trapped therein begin to ignite, the ignition of aninitial portion of soot particles trapped therein can cause the ignitionof the remaining soot particles much in the same way a cigar slowlyburns from one end to the other. In essence, as the soot particles“burn,” an amount of heat is released in the “burn zone.” Locally, thesoot layer (in the burn zone) is now much hotter than the immediatesurroundings. As such, heat is transferred to the as yet un-ignited sootlayer downstream of the burn zone. The energy transferred may besufficient to initiate oxidation reactions that raise the un-ignitedsoot to a temperature above its ignition temperature. As a result ofthis, heat from the fuel-fired burner 16 may only be required tocommence the regeneration process of the filter 18 (i.e., begin theignition process of the soot particles trapped therein).

As shown in FIG. 1, one method of supplying sufficient oxygen forregeneration of the filter 18 includes the engine 12 being configuredfor exhaust gas recirculation (EGR). In this exemplary embodiment, anEGR line 22 connects the exhaust line 27 and the engine 12 to oneanother. The EGR line 22 allows a portion of exhaust gases to berecirculated into the engine intake (not shown) along with drawn-incombustion air and ultimately into the combustion chamber 13 of engine12, which reduces the amount of emissions present in exhaust gasesexiting the engine 12. However, in operation, the amount of recirculatedexhaust gases supplied to the engine 12 replaces a corresponding amountof the combustion air supplied. This causes less oxygen to be present inthe combustion chamber 13, which results in less oxygen being present inthe exhaust gases generated by the engine 12.

In this exemplary embodiment, an EGR valve 24 is shown disposed alongthe EGR line 22 between the exhaust line 27 and the engine 12. The valve24 can be operated to control the amount of recirculated exhaust gasessupplied to engine 12. When the valve 24 is operated to reduce theamount of exhaust gases supplied to the combustion chamber 13 of theengine 12, more air can be supplied to the combustion chamber 13 throughthe intake of the engine 12. Allowing more air, in contrast to exhaustgases, to enter the combustion chamber 13 of the engine 12 will generateexhaust gases exiting the engine 12 containing more oxygen than that ofexhaust gases generated with the valve 24 being fully open. This allowsmore oxygen to be supplied to the fuel-fired burner 16 for regenerationof the filter 18. The valve 24 may be completely closed to allow onlyair and fuel to be present in the combustion chamber 13 for combustion.

As shown in FIG. 1, a controller 25 may be responsible for interpretingelectrical signals sent by sensors associated with the emissionabatement assembly 10 (and in some cases, the engine 12) and foractivating electronically-controlled components associated with theemission abatement assembly 10. For example, the controller 25 may beoperable to, amongst many other things, determine when the particulatefilter 18 of the soot abatement assembly 14 is in need of regeneration,calculate and control the amount of fuel to be introduced into thefuel-fired burner 16, determine the temperature in various locationswithin the soot abatement assembly 14, operate numerous air and fuelvalves, and communicate with an engine control unit (not shown)associated with the engine 12.

To do so, the controller 25 includes a number of electronic componentscommonly associated with electronic units utilized in the control ofelectromechanical systems. For example, the controller 25 may include,amongst other components customarily included in such devices, aprocessor such as a microprocessor or microcontroller and a memorydevice such as a programmable read-only memory device (“PROM”) includingerasable PROM's (EPROM's or EEPROM's). The memory device is provided tostore, amongst other things, instructions in the form of, for example, asoftware routine (or routines) which, when executed by the processor,allows the controller 25 to control operation of the emission abatementassembly 10. The controller 25 may also be configured to receive signalsfrom either analog or digital sensors used in the emission abatementassembly 10.

The controller 25 may control operation of the fuel-fired burner 16through a control line 17. In particular, the controller 25 may controlthe amount of fuel injected into the fuel-fired burner 16 by controllingthe appropriate control signals on the control line 17. The memorydevice may store the fuel quantities necessary for the regeneration ofthe filter 18. This allows controller 25 to ensure that the appropriateamount of fuel is used for producing sufficient heat to ignite the sootin the filter 18. The controller 25 can determine if regeneration of thefilter 18 is required through a sensor 29. The sensor 29 may sense thepressure drop across the filter 18 to determine if regeneration isnecessary and transmit a signal indicating such through a control line19 to the controller 25. When the particulate filter 18 is to beregenerated, the controller 25 may control the valve 24 through acontrol line 21 to reduce the amount of recirculated exhaust gasessupplied to the combustion chamber 13, allowing the oxygen content ofthe exhaust gases supplied to the fuel-fired burner 16 to increase. Itshould be appreciated that the control scheme utilized to initiatefilter regeneration may be designed in a number of different manners.For example, a timing-based control scheme may be utilized in which theregeneration of the particulate filter 18 is commenced as a function oftime. For instance, regeneration of the particulate filter 18 may beperformed at predetermined timed intervals.

FIG. 2 shows another exemplary embodiment of the emission abatementsystem 10. In this illustrative embodiment, a turbocharger 26selectively supplies air to the combustion chamber 13 of engine 12.Similar to that shown in FIG. 1, the exemplary embodiment of FIG. 2 isconfigured to increase the amount of oxygen in the exhaust gasesallowing the fuel-fired burner to heat the exhaust gases flowing throughthe exhaust system to reach temperatures high enough to ignite soottrapped in the soot particulate filter 14. Typically, the turbocharger26 includes a compressor 28 and a turbine 30. In this illustrativeembodiment, the turbocharger 26 is located downstream of the engine 12.An inlet 32 of turbine 30 receives the exhaust gases flowing from engine12, which causes the turbine 30 to rotate. The exhaust gases exit theturbine 30 through outlet 31 and continue to move downstream to the sootabatement assembly 14. The motion of the turbine 30 causes thecompressor 28 to pull in air through intake 33 and send compressed airthrough outlet 34 and into the combustion chamber 13 of engine 12.

The turbocharger 26 can be selectively operated during times when theparticulate filter 18 needs to be regenerated. Specifically, thecontroller 25 may be used to selectively operate the turbocharger 26through a control line 23. As described in FIG. 1, the controller 25 maydetermine if the filter 18 needs regenerated based upon input fromsensors, such as the sensor 29, used in the emission abatement system 10allowing the controller 25 to operate the turbocharger 26 at theappropriate times. It should be appreciated that the decision toregenerate the particulate filter can be a time-based decision, aspreviously described herein.

During the periods of filter regeneration, the turbocharger 26 sendscompressed air into the combustion chamber 13 of the engine 12. Thiscauses more oxygen to be present in the exhaust gases exiting the engine12 than would otherwise be present without operating the turbocharger26. The increased level of oxygen allows the fuel-fired burner 16 toheat the exhaust gases to a temperature high enough to regenerate thesoot particulate filter 18. It should be appreciated that theturbocharger 26 may be a variable-speed or single-speed unit. Avariable-speed unit allows the rate of compressed air being supplied tothe combustion chamber 13 to be controlled over an operating range,whereas a single-speed unit supplies compressed air at a constant rate.

It should be appreciated that the engine 12 may include a number ofcombustion chambers 13 as is typically found in diesel engines. In FIG.1, the engine 12 may be configured to allow the recirculated exhaustgases to be supplied to each combustion chamber 13, with the valve 24reducing the amount of exhaust gases supplied to each combustion chamber13. In FIG. 2, the engine 12 may be configured to allow the compressedair supplied by the turbocharger 26 to reach each combustion chamber 13.

FIG. 3 shows an exemplary emission abatement system 10 implementingturbochargers 26 a through 26 n. In this exemplary embodiment, multipleturbochargers 26 are serially connected such that the outlet 34 of eachcompressor 28 is connected to an inlet 33 of an adjacent compressor 28as shown in FIG. 3. Compressor 28 a is shown as having an outlet 34 acoupled to inlet 33 b of compressor 28 b.

During operation, all the turbochargers 26 can be operated such that airis first drawn into the inlet 34 a of the compressor 28 a. The air movesthrough each compressor 28 such that it is continuously compressed as itmoves through. Eventually, the compressed air exits outlet 34 n ofturbocharger 26 n and into the combustion chamber 13. Thus, theconfiguration shown in FIG. 3 can be used to supply air to thefuel-fired burner 16 for regeneration of the filter 18 in a mannersimilarly described in regard to FIG. 2.

As the exhaust gases exit the engine 12, they pass through each turbine30. Each turbocharger 26 includes a control line 23, which can be usedto selectively operate each turbocharger 26 independently. As describedin FIG. 2, each turbocharger may be a variable-speed or single-speedunit and controlled accordingly. In a configuration using variable-speedturbochargers 26, each turbine 30 can be independently operated so thatthe amount of “boost” provided by the turbochargers 26 to the engine 12can be more particularly controlled.

FIG. 4 shows another exemplary embodiment of an emission abatementassembly 10 implementing a supercharger 40. Supercharger 40 includes aninlet 42 which draws in air and is compressed therein and subsequentlyexpelled through an outlet 44. In FIG. 4, the supercharger 40 isconfigured to provide oxygen to the combustion chamber 12 of an internalcombustion engine 12, which can be subsequently provided to thefuel-fired burner 16 for regeneration of the filter 18. In one exemplaryembodiment, the engine 12 is gasoline-powered.

The supercharger 40 can be operated mechanically or electrically by theengine 12 as indicated by arrow 46. For example, in one exemplaryembodiment the supercharger 40 can include a belt-driven air pump (notshown) using rotational motion provided by the engine for rotating thebelt. In another exemplary embodiment, the supercharger 40 includes anelectrically-driven pump (not shown), which can receive power from asource within an engine, such as from a battery. It should beappreciated that the supercharger 40 may be a variable-speed orsingle-speed unit. A variable-speed unit allows the rate of compressedair being supplied to the combustion chamber 13 to be controlled over anoperating range, whereas a single-speed unit supplies compressed air ata constant rate.

Control line 43 can provide control signals to the supercharger 40 fromthe controller 25, allowing the supercharger to be selectively operatedsuch as at times when regeneration of the filter 18 is desired. Itshould be appreciated that the supercharger 40 may be a variable-speedor single-speed unit. A variable-speed unit allows the rate ofcompressed air being supplied to the combustion chamber 13 to becontrolled over an operating range, whereas a single-speed unit suppliescompressed air at a constant rate.

It should be appreciated that the methods disclosed herein can beapplied to other emission abatement components other than particulatefilters. For example, the emission abatement assembly 10 can use adevice for abating oxides of nitrogen (NOx), such as a selectivecatalytic reduction (SCR) catalyst. Typically, the efficiency of NOxabatement devices can be increased by raising the temperature of theexhaust gases flowing therethrough. Accordingly, the fuel-fired burner16 can be operated in the various manners disclosed herein to raiseexhaust gas temperature. Furthermore, the oxygen content present in theexhaust gases can be adjusted in the various manners disclosed hereinfor supplying desired amounts of oxygen to the burner 16 for combustion.This allows the temperature of the exhaust gases to be raised beforereaching a NOx abatement device disposed downstream of the burner 16.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the apparatus and methods described herein.It will be noted that alternative embodiments of the apparatus andmethods of the present disclosure may not include all of the featuresdescribed yet still benefit from at least some of the advantages of suchfeatures. Those of ordinary skill in the art may readily devise theirown implementations of an apparatus and method that incorporate one ormore of the features of the present disclosure and fall within thespirit and scope of the present disclosure.

1. A method of operating an emission abatement assembly, comprising thesteps of: determining if a particulate filter needs to be regeneratedand generating a signal in response thereto, adjusting the operation ofan internal combustion engine to increase the oxygen content in exhaustgases generated by the engine in response to the generation of thesignal, advancing the exhaust gases to a fuel-fired burner, andgenerating heat with the fuel-fired burner to combust soot trapped in aparticulate filter.
 2. The method of claim 1, wherein the determiningstep comprises measuring the pressure drop across the particulate filterto determine that the particulate filter needs regenerated.
 3. Themethod of claim 1, wherein the determining step comprises generating thesignal with a sensor indicating that the particulate filter needs to beregenerated, and transmitting the signal to a controller.
 4. The methodof claim 1, wherein the adjusting step comprises reducing an amount ofrecirculated exhaust gases entering a combustion chamber of the enginein response to the generation of the signal to increase the oxygencontent in the exhaust gases generated by the engine.
 5. The method ofclaim 4, wherein the adjusting step further comprises operating an EGRvalve in response to the generation of the signal to reduce the amountof recirculated exhaust gases entering the combustion chamber of theengine.
 6. The method of claim 5, wherein the adjusting step furthercomprises operating the EGR valve with a controller in response to thegeneration of the signal to reduce the amount of recirculated exhaustgases entering the combustion chamber of the engine.
 7. The method ofclaim 1, wherein the adjusting step comprises operating a turbochargerto supply air to a combustion chamber of the engine in response to thegeneration of the signal to increase oxygen content in the exhaust gasesgenerated by the engine.
 8. The method of claim 7, wherein the operatingstep further comprises operating the turbocharger with a controller tosupply air to a combustion chamber in response to the generation of thesignal to increase the oxygen content in the exhaust gases generated bythe engine.
 9. The method of claim 7, wherein the operating step furthercomprises operating a turbine of the turbocharger, operating acompressor of the turbocharger with the turbine, and supplyingcompressed air from the compressor to the combustion chamber of theengine to increase the oxygen content of the exhaust gases generated bythe engine.
 10. The method of claim 7, wherein the adjusting stepfurther comprises operating a plurality of turbochargers to supply airto a combustion chamber of the engine in response to the generation ofthe signal to increase oxygen content in the exhaust gases generated bythe engine.
 11. The method of claim 10, wherein the operating stepfurther comprises operating the plurality of turbochargers with acontroller to supply air to a combustion chamber in response to thegeneration of the signal to increase the oxygen content in the exhaustgases generated by the engine.
 12. The method of claim 1, wherein theadjusting step comprises operating a supercharger to supply air to acombustion chamber of the engine in response to the generation of thesignal to increase oxygen content in the exhaust gases generated by theengine.
 13. The method of claim 12, wherein the operating step furthercomprises operating the supercharger with a controller in response tothe generation of the signal to increase the oxygen content in theexhaust gases generated by the engine.
 14. An emission abatementassembly, comprising: an internal combustion engine, a particulatefilter, a fuel-fired burner positioned upstream of the particulatefilter, the fuel-fired burner having an input that receives exhaustgases generated by the internal combustion engine, and a controllerelectrically coupled to the internal combustion engine and thefuel-fired burner, the controller comprising (i) a processor, and (ii) amemory device electrically coupled to the processor, the memory devicehaving stored therein a plurality of instructions which, when executedby the processor, cause the processor to: determine if the particulatefilter needs to be regenerated and generate a control signal in responsethereto, adjust the operation of the internal combustion engine toincrease the oxygen content in exhaust gases generated by the engine inresponse to the generation of the control signal, and operate thefuel-fired burner to generate heat to combust soot trapped in theparticulate filter in response to the generation of the control signal.15. The emission abatement assembly of claim 14 further comprising asensor, wherein the plurality of instructions, when executed by theprocessor, further cause the processor to determine if the particulatefilter needs to be regenerated by measuring the pressure drop across theparticulate filter with the sensor.
 16. The emission abatement assemblyof claim 14 further comprising an EGR valve, wherein the plurality ofinstructions, when executed by the processor, further cause theprocessor to adjust the operation of the internal combustion engine byoperating the EGR valve in response to the generation of the controlsignal to reduce the amount of recirculated exhaust gases entering thecombustion chamber of the engine.
 17. The emission abatement assembly ofclaim 14 further comprising a turbocharger, wherein the plurality ofinstructions, when executed by the processor, further cause theprocessor to adjust the operation of the engine by operating theturbocharger to supply air to a combustion chamber of the engine inresponse to the generation of the control signal to increase oxygencontent in the exhaust gases generated by the engine.
 18. The emissionabatement assembly of claim 17, wherein the turbocharger comprises aturbine and a compressor, wherein the plurality of instructions, whenexecuted by the processor, further cause the processor to adjust theoperation of the engine by, operating the compressor with the turbine,and wherein, the compressor supplies compressed air from the compressorto the combustion chamber of the engine to increase the oxygen contentof the exhaust gases generated by the engine.
 19. The emission abatementassembly of claim 17, wherein the turbocharger comprises a plurality ofturbochargers, wherein the plurality of instructions, when executed bythe processor, further cause the processor to adjust the operation ofthe engine by operating the plurality of turbochargers to supply air toa combustion chamber of the engine in response to the generation of thecontrol signal to increase oxygen content in the exhaust gases generatedby the engine.
 20. The emission abatement assembly of claim 14 furthercomprising a supercharger, wherein the plurality of instructions, whenexecuted by the processor, further cause the processor to adjust theoperation of the engine by operating the supercharger to supply air to acombustion chamber of the engine in response to the generation of thecontrol signal to increase oxygen content in the exhaust gases generatedby the engine.
 20. (canceled)
 21. The emission abatement assembly ofclaim 14, wherein the fuel-fired burner is operated without asupplemental air supply.
 22. A method of operating an emission abatementassembly, comprising the steps of: determining if a predeterminedcondition of an emission abatement component exists and generating asignal in response thereto, adjusting the operation of an internalcombustion engine to increase the oxygen content in exhaust gasesgenerated by the engine in response to the generation of the signal,advancing the exhaust gases to a fuel-fired burner, generating heat withthe fuel-fired burner to heat the exhaust gases, and advancing theheated exhaust gases to the emission abatement component.
 23. The methodof claim 22, wherein the determining step comprises determining if apredetermined condition of a NOx abatement device exists and generatinga signal in response thereto.
 24. The method of claim 22, wherein thedetermining step comprises determining if a predetermined conditions ofa particulate filter exists and generating a signal in response thereto.25. The method of claim 1, wherein the advancing step comprisesproviding an exhaust line between the engine and the fuel-fired burnerthat defines an exhaust gas path, and feeding the engine exhaust gasesinto the fuel-fired burner through the exhaust line.
 26. The method ofclaim 1, wherein the fuel-fired burner only receives oxygen from exhaustgases generated by the engine.
 27. The emission abatement assembly ofclaim 14, including an exhaust line fluidly connecting the internalcombustion engine to the inlet of the fuel-fired burner, and wherein theexhaust gases are fed into the fuel-fired burner through the exhaustline.
 28. The emission abatement assembly of claim 14, wherein thefuel-fired burner only receives oxygen from exhaust gases generated bythe internal combustion engine.
 29. The method of claim 22, wherein theadvancing step comprises providing an exhaust line between the engineand the fuel-fired burner that defines an exhaust gas path, and feedingthe engine exhaust gases into the fuel-fired burner through the exhaustline.
 30. The method of claim 22, wherein the fuel-fired burner onlyreceives oxygen from exhaust gases generated by the engine.
 31. Theemission abatement assembly of claim 14, wherein the exhaust gases areadvanced from the engine to the fuel-fired burner to generate heat tocombust soot trapped in the particulate filter.